Silver halide emulsion

Details Silver halide emulsion Silver halide emulsion

2001-11-14

2003-10-28

Baxter, Janet (Department: 1752)

Radiation imagery chemistry: process, composition, or product th

Radiation sensitive product

Silver compound sensitizer containing

C430S569000

Reexamination Certificate

active

06638702

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a silver halide emulsion to be used in a silver halide photographic photosensitive material (i.e., a silver halide photographic light-sensitive material). In particular, the present invention relates to a silver halide emulsion having a high photosensitivity and a high gradation without reciprocity law failure owing to dopant techniques.
BACKGROUND OF THE INVENTION
As one of techniques of quality modification of silver halide grains for improving properties of the entire silver halide photographic photosensitive material as desired, there is known a technique (a doping technique) of incorporating other substance (a dopant) in addition to silver ions and halide ions.
Particularly, many studies have been done on doping techniques of transition metal ions. It is generally recognized that transition metal ions modify photographic properties effectively when they are incorporated into silver halide grains as a dopant even in an extremely small addition amount.
In order to improve photographic properties of a silver halide emulsion more effectively, not only techniques of doping transition metal ions but also techniques of doping transition metal complexes have been known. For obtaining an emulsion having a high photosensitivity, there are lots of disclosures of emulsions doped with a metal (in the group VIII of the periodic table) complex, particularly, taking six cyanide ions as ligands.
Hexacyano ferrate (II) complexes and hexacyano ferrate (III) complexes as a dopant including a cyanide ion are disclosed in (examined) Japanese Patent Publication No. 35373/1973. There are many other examples of obtaining a highly photosensitive emulsion by doping a hexacyano ferrous (II) complex, for example, disclosures in Japanese Patent Application Laid Open No. 66511/1993 (The term “Japanese Patent Application Laid Open” means an unexamined published Japanese Patent application”) and U.S. Pat. No. 5,132,203. Highly photosensitive emulsions obtained by doping other cyano complexes than an iron complex are known. Namely, it is disclosed in Japanese Patent Application Laid Open No. 20853/1990 that a highly photosensitive emulsion is obtained by doping a complex of rhenium, ruthenium, osmium or iridium into silver iodochloride. In order to improve reciprocity law failure, in particular, high intensity reciprocity law failure, an iridium complex is used. Examples of doping an iridium complex into silver halide grains are disclosed in Japanese Patent Application Laid Open Nos. 285941/1989, 118583/1991, 213449/1992, 278940/1992, 66511/1993, 313277/1993, 82947/1994, 235995/1994, 72569/1995, 72576/1995, 202440/1999 and 295841/1999, wherein H
2
O, cyano, nitrosyl or thionitrosyl is used as a ligand for an iridium complex.
Gradient is one of important photographic properties of the sliver halide emulsion. A doping technique is also used for obtaining a sliver halide emulsion having a high gradient.
As disclosed in European Patents 033642, 0606895 and 0610670, techniques using nitrosyl or thionitrosyl as a ligand of a transition metal complex are known for obtaining a high gradient emulsion, namely, an emulsion having a high contrast. In this case, ruthenium or osmium is mainly used as a central metal.
Besides using nitrosyl or thionitrosyl, effectiveness of using hexachloro ruthenium, hexachloro rhodium or hexachloro rhenium for obtaining a contrast-increasing emulsion is described in Japanese Patent Application Laid Open Nos. 184740/1988, 285941/1989, 20852/1990 and 20855/1990.
Further, in recent years, techniques of doping a complex having an organic compound as its ligand into silver halide grains to modify properties of the emulsion have been disclosed. Many examples of using a complex having an organic compound as its ligand are shown in U.S. Pat. Nos. 5,360,712, 5,457,021 and 5,462,849, European Patent 0709724, and Japanese Patent Application Laid Open Nos. 71569/1995 and 179452/1996. Particularly, it is described in the above references that remarkable effects of increasing photosensitivity are obtained when [(NC)
5
Fe(&mgr;-4,4′-bipyridine)Fe(CN)
5
]
6−
is doped, and further that high intensity reciprocity law failure is effectively improved when [IrCl
5
(thia)]
2−
is doped. Emulsions having a high photosensitive with improved reciprocity law failure are obtained in Japanese Patent Application Laid Open No. 24194/1999 by doping [Fe(CO)
4
(P(Ph)
3
)]
0
or [Fe(CO)
3
(P(Ph)
2
)]
0
. Also, highly photosensitive emulsions are obtained in Japanese Patent Application Laid Open No. 102042/1999 when L is 2-mercaptobenzimidazole, 5-methyl-s-triazolo(1.5-A)pyrimidine-7-ol or 2-mercapto-1,3,4-oxadoazole in the complexes of [M(CN)
5
L]
3−
(M=Fe
2+
, Ru
2+
or Ir
3+
), [Fe(CO)
4
L]]
0
, [M′(CN)
3
L]
−
(M′=Pd
2+
or Pt
2+
), or [IrCl
5
L]
−
type. Further, it is indicated in Japanese Patent Application Laid Open No. 293377/1998 that are markable contrast-increasing emulsion is obtained when [RuCl
5
L′]
2−
(L′=imidazole, benzimidazole or derivative thereof) is doped, and that the photosensitivity of the emulsion becomes drastically higher than that of an emulsion using a conventional dopant for obtaining high contrast with desensitization.
These dopants improve photographic properties effectively even when a single dopant is solely used. However, when a plurality of dopants are simultaneously used, an emulsion having each quality of dopants in combination can be obtained.
For obtaining an emulsion having both of a high photosensitivity and a high contrast, techniques of using a combination of a ruthenium complex or an osmium complex with nitrosyl as a ligand of complex and an iron complex or a ruthenium complex with a cyanide ion as a ligand are disclosed in U.S. Pat. No. 5,480,771 and European Patents 0606893, 0606894, 0606895 and 0610670. An emulsion having a high photosensitivity and no reciprocity law failure is realized by using a hexacyano complex and an iridium complex in combination as disclosed in Japanese Patent Application Laid Open Nos. 125425/1990, 132647/1991 and 188437/1991. An emulsion having a high contrast and an excellent property in low intensity and/or high intensity reciprocity law failure can be obtained by using a combination of a ruthenium complex or an osmium complex with nitrosyl as a ligand of complex and an iridium complex as described in U.S. Pat. Nos. 5,474,888 and 5,500,335 and Japanese Patent Application Laid Open No. 51233/1992.
Further, by using three kinds of dopants in combination, an emulsion having a high photosensitivity, a high contrast and less reciprocity law failure can be obtained. Such emulsions having a high photosensitivity, a high contrast and less reciprocity law failure by using hexacyano ruthenium (II) as a dopant for high photosensitivity, pentachloronitrosyl osmium (II) as a dopant for high contrast and hexachloro iridium (III or IV) as a dopant for improving reciprocity law failure are disclosed in Japanese Patent Application Laid Open Nos. 314043/1996, 328182/1996, 211529/1996 and 211530/1996 and U.S. Pat. No. 5,480,771. In addition to the above, disclosure examples of using three kinds of dopants include descriptions in Japanese Patent Application Laid Open No. 282114/1999. In this example, by using pentachloronitrosyl osmium, hexachloro iridium and pentachloro(thiazole)iridium in combination, an emulsion having a high contrast and no reciprocity law failure in a broad range of exposure light intensity is obtained.
However, there is no disclosure example of a silver halide emulsion using four kinds of dopants in combination and of an emulsion using a dopant with a cyanide ion as a ligand, which is a dopant for high photosensitivity, and three or more kinds of dopants in combination. Any example that an emulsion having a high photosensitivity, no reciprocity law failure in a broad range of e

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